Tack On The Fritz

My tackometer works most of the time. However, occasionally I will look down and I have lost the Tack. I have a 2001 Buick Park Avenue with a 3.8L engine. Most recently I had to turn off the key to reset the Tack. I could use some feedback on possible ways to troubleshoot this problem.

Thanks

You need a wiring diagram for a 2001. It could be a cluster problem, but it might be a bad wire or bad connection. For a '97, the tach reads from a wire (white) that comes from near the ignition module and coils. It reads from the crank position sensor. It sends a signal to the ECM to tell it rpms and crankshaft position. If the circuit fails, it should set a code, or the engine will stumble and not start. Have any codes? If not, it may be the tach gauge itself. I had to replace my instrument cluster due to a jumpy tach and speedometer.

I have no codes. It might be the instrument cluster. Especially if you had a jumpy tack and repaired the problem with a new cluster. Thanks for the reply.

Mine would always work, but it jumped and kind of skipped. From what I recall, it was never completely dead. Could even be there is a bad connection somewhere, possibly between the ECM and the gauge. There may be a way to read the tach wire with a digital voltmeter. I ended up putting in a salvaged cluster. My speedometer would go from 0 to 20 while sitting still at a stoplight.

Thanks for the feedback smith1000. Mine works flawlessly but has occasional total shutdowns. It could be the wire. I will check the 2001 wiring diagram and make sure the wire from ECM is connected and has continuity. Beyond that my thought is that the cluster is having issues. I had a 2003 Avalanche with speedometer issues and we replaced the cluster and my problems went away. Have a great day.

Sir,

I had a *speedometer* problem on our '97. The problem turned out to be a bad connection on the IPC circuit board. In our case both the speedometer and odometer quit from time-to-time. I put it on the bench and applied +12V and generated an artificial speedometer signal to find the problem. In solving the intermittency, I also found that the speedometer was off in speed. The specs say +/- 4 MPH and I guess that explains it. Likely the tach can also err by some amount.

Regards,
Jack C.